they are different for sure.
when i had dropped the sensitivity on my xs just a few numbers, depth loss was substantial. not true with the xsII i have. i think most folks who have tried both will agree. you can drop the sensitivity down on the xsII and it's still deep. they're different for sure in some ways.
the depth reading seems to be different too. sometimes targets are deeper than the depth guage indicates with the xsII. at least this is what i've experienced.
i can't say that i noticed a faster processor speed with the xsII. maybe there isn't that much difference there.
when i tested them side by side though, using the same high sensitivity settings, i couldn't tell any difference in detection depth. i was testing deep coins.
the xsII gives you two numbers for id in the digital mode, ferrous and conduct, while the xs only gives you a conduct number. the dual numbers of the xsII are great for targets up to about 5-6" deep. any deeper than that and you probably better be using the smartscreen or those numbers will be jumping all over the place.
first time out with my new xs, the fricken yoke cover fell off and was laying in the yard. i thought....what the hell? i come to find out later....oh that happens all of the time to the xs. <img src="/metal/html/lol.gif" border=0 width=15 height=15 alt=":lol"> some don't even have a yoke cover anymore. probably lost in the woods somewhere. hee hee.
then, after one more use, the thing went BONKERS. the menu button now turned on the backlight. so i couldn't access the menu, and the backlight button didn't do anything, geeez. i thought what a pos, only owned it for like two weeks. <img src="/metal/html/cry.gif" border=0 width=40 height=15 alt=":cry"> had to send it in for warranty work, needed a new touch screen. after that, it was fine. good thing i had bought a new ploder with a warranty. <img src="/metal/html/wink.gif" border=0 width=15 height=15 alt="

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after that, my ploder was hot, i was digging stuff up like i couldn't believe. conn. copper, LC, seated, dozens of silvers from the deep, weeeeeee. <img src="/metal/html/biggrin.gif" border=0 width=15 height=15 alt="

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oh...and that's another difference. the touchpad buttons on the xsII are clickier, feel stronger.
but, what really attracted me to the xsII though was the 4 year free warranty special, and $50 rebate, got a free 8" ML coil with it too. whoopee! well. it's worth something.
the new lower rod on the xsII is just awesome compared to the old xs lower rod. but, guess what? the new black lower rod fits the xs too, so you can just buy one and put it on the xs.
when i got my xsII, then i could retract the lower rod, and it made it easier to store and transport.
that old style lower rod will jamb up, grind up, and will get stuck. it fricken wobbles, bends, and flexes like a 2 iron flex shaft. in my opinion, it's a pos!
so, the choice is yours, ploder or xsII. <img src="/metal/html/shocked.gif" border=0 width=15 height=15 alt=":shock">
anyway, i hope this helps. <img src="/metal/html/wink.gif" border=0 width=15 height=15 alt="

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and that's my story, and i'm sticking to it. <img src="/metal/html/tongue.gif" border=0 width=15 height=15 alt=":b">